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How to Develop Sour Flavor in Sourdough

April 10, 2008 - 5:19am

SourdoughSam

How to Develop Sour Flavor in Sourdough

How to Develop Sour Flavor in Sourdough

I just posted this as a response to a query, but thought that it deserved to be posted as a separate topic. I spent months trying to figure this out, and there was so much inaccurate information posted on the internet on the subject, that I thought this would be useful to lots of people trying to figure out the "secret" of developing sour flavor in sourdough. It's a heck of a lot simpler than most people seem to think.

In short, there are three key factors in the development of flavor in sourdough:

The ash content of the flour is a key issue for development of total acidity (TTA - Total Titratable Acids) and flavor. The higher the ash content, the higher the buffering capacity. The buffering capacity of the flour reduces the volatile acidity (pH) of the dough, allowing the bacteria to work longer before they over-acidify their environment and stop producing acids and flavor compounds. In addition, ash content is critical for allowing the bacteria to develop amino acids and volatile flavor compounds that contribute to that signature sourdough flavor. While sourness can be obtained using a low ash content flour, the bread will contain a lesser overall acidity, and will contain fewer amino acids and volatile flavor compounds that contribute to flavor. All purpose flour normally does not have a high enough ash content to allow substantial flavor development. High gluten flour (aka bread flour) usually does. Whole wheat and rye breads have an even higher ash content, which is why people are often more successful in developing sourness and flavor in doughs containing these flours.

The fermentation time must be LONG, meaning 12 to 20 hours. Acidity and flavor develops during fermentation of the dough, and it takes the bacteria a long time to do it. If you ferment your bread for less than about 8 hours, you'll get a very tasty, but non-sour bread.

The fermentation temperature should be between 20C and 30C. Any less, and you're simply slowing down the bacteria in their quest to eat food and develop flavor. Any more, and you're overheating them and hindering their growth. However, anything within the indicated range is just fine. Bacteria do produce some different volatile flavor compounds below 25C than they do above 25C, so this is one way to fine-tune the flavor of your bread, if you so desire.

For more information on the above, here's an excellent, freely available paper on the subject:http://ethesis.helsinki.fi/julkaisut/maa/elint/vk/katina/Katina, Kati, "Sourdough: a tool for the improved flavour, texture and shelf-life of wheat bread"Academic Dissertation, August 2005.University of Helsinki, Faculty of Agriculture and Forestry, Department of Food Technology.ISBN 951-38-6650-5

Here's a VERY SIMPLE procedure for creating a bread with a fully-developed sour flavor with any starter (I've got a collection of three of them, including Carl's 1847 Oregon Trail Starter, and this technique works wonders with all of them).

Step 1 - Make a fairly stiff dough using 5% to 20% starterStep 2 - Place in oiled bowl, cover with plastic wrap, and let sit at room temperature for 12-15 hours (no need to punch down, worry, fret, or whatever... just let it sit).Step 3 - Gently remove from bowl* and bake.

Yep, that's it. After months of trying to figure out how to get that sourdough flavor, trying various complicated methods involving overnight refrigeration, letting the starter go sour, multiple starter stages, chanting of mystical incantations, etc., I found out that you just make the dough and let it sit on your kitchen counter. How's that for uncomplicating things?

Hope this clarifies things a bit. Good luck with your sourdough baking!

SourdoughSam

* I usually scrape the dough from the bowl with a spatula directly onto an oiled baking sheet, slash the top, and bake. No shaping and re-proofing necessary if you're simply making a round boule or carefully stretching the dough into baguettes. If you want to shape the bread otherwise, you should do so 3 to 5 hours before baking.

11 Apr 2008 - Made some updates and changes based on the excellent comments posted in response.

13 Apr 2008 - Added note regarding shaping, clarifications regarding the effect of ash content on acidity, and a note that different flavor compounds are produced below and above 25C.

There's no real ash actually 'contained' in the flour. Its "stuff that turns into ash rather than gas when its burned" that's being measured.

And that's a measure of the mineral content.

Which in turn is a measure of how much bran is in the flour - ie how much bran has *not* been removed in the milling process.

So "ash" indicates bran/minerals.

There's a related bit of terminology that confuses many. "High extraction" means a flour with rather a lot of its bran still there. So a low ash flour, with very little trace of bran will be referred to as a "low extraction" flour. Strange, huh?

The French make baguettes with white flour graded T55 or sometimes T65. The higher the number, the more "ash", minerals and bran. T150 is 100% wholegrain flour. T80 is nice tasty stuff that you can simulate (roughly) by sieving out the coarsest bran from a wholegrain/wholemeal flour.

Now, buffering capacity. To a chemist, this would mean the ability of a system to soak up acid while barely changing in acidity (or alkali with little change in alkalinity). I've not personally encountered this in sourdough discussion before, but certainly mineralisation might affect whether or not there was buffering in a sourdough culture. I wouldn't have expected it to be a massive effect, and I'm not sure its helpful to suggest that "Ash Content" is "aka Buffering Capacity"... but hey, its one more thing for me to check out and continue learning!

Ash content is basically the mineral content of flour. The mineral content is mainly in the seed coat of the berry, so flours that are very refined, i.e. pure white flours, tend to have very low ash content. They contain only the white starch and protein of the inner endosperm. Higher ash content flours will have a greater proportion of matter coming from the outer parts of the berry, i.e. the outer endosperm, the surface under the bran, and the bran.

The reason the term ash content is used is because there is a standard test used to analyze materials, particularly grains, crops of various types, and flour. The test involves incinerating the material in a furnace at a high temperature (e.g. 600-900F) for a long time (e.g. 24 hours) until all the burnable or volatile material is gone. The only material left (the ash) is weighed as a percentage of the original material. That is the ash content. It is a measure of the mineral content.

If the buffering capacity is proportional to the mineral content, then the buffering capacity of a flour with 1% ash content, typical of a high extraction flour, would be double that of the typcial white flour with 0.5% ash content. I'm not a chemist, but to me this means that the acids in the 1% ash content flour can reach double the concentration of the 0.5% ash content flour before the pH drops below about 3.9, which is roughly the pH where a fermentation begins to slow way down and overproofing becomes an issue.

As has already been mentioned, most consumer flours don't have this information printed on the label. You can often find it on the manufacturer's web page under nutritional infomration. Sometimes it takes a bit of digging to find the information.

If it's not available, the vendors will usually give you the information if you send them an email asking for it.

GM's Harvest King has a minumum ash level of .54%

King Arthur's flours are all rated as +/- .02% of the numbers give below

Sir Lancelot .52%

Special .48%

Sir Galahad .48%

Whole Wheat 1.8%

Round Table .44%

Queen Guinivere .34%

Baker's Classic .60%

Select Artisan Flour .54%

Baker's Select with Restored germ .60%

Big-O Hi-Gluten .55%

Organic Whole Wheat > 1.4%

I couldn't find the numbers at Bob's Red Mill, but they'd tell you if you asked.

I like your explanation of the key factors that affect sour very much.

I think you are right that the sour flavor develops mainly in the bread itself, and that higher ash content/buffering capacity of the flour is the key to allowing the acid to build up to the point where sour flavor develops before the drop in pH shuts off the Lactobacillus activity.

I also agree that temperature and time greatly affect the fermentation progress, and therefore the development of sour flavor. At lower temperatures the mix to bake time will be much longer to achieve the same amount of fermentation progress and sour flavor development.

I'd like to add one more variable to the discussion, which is the tolerance of the flour to sourdough acids. It's possible to have a low gluten, high ash flour that may develop a high acidity before the pH drops and bacterial activity slows, but if the flour won't tolerate the acids, the bread will collapse before the sour develops. So, I'd just add that you can get more sour bread with higher protein flour than lower, for the same ash content.

At least in terms of experience, I've also found that you can make a more sour bread with a stiffer dough. You can ferment a stiff dough to the point it is more sour before it shows signs of overproofing. I'm not sure which of the factors above contribute to that result. Per unit of flour, the buffering capacity should be the same, I would've thought, whether the dough is stiff or not. However, the conditions in the dough may favor the Lactobacillus activity over the yeast, as the dough rises, and maybe the gluten in the stiffer dough can last longer relative to the acid build-up. In any event, I've definitely had more luck making sour bread with stiffer dough.

I'm very pleased to see the amount of interest that the original post has generated on this topic. Thanks to all who have responded, and particularly to Bill Wraith, who has pointed out a couple of things that I wouldn't even have considered. I should have qualified my original post to say that my results were obtained using doughs with hydrations of 50% to 60% and high gluten flours. My "simple procedure" may not work with doughs of other hydrations or low gluten flours (although I can say for sure that it works with 100% whole wheat dough made from coarse flour ground in a kitchen blender from 100% crushed wheat breakfast cereal... they don't sell whole wheat flour where I live!).

Perhaps the thing that drove me to make this post in the first place is that I simply couldn't find a straight answer on the internet about how to control the flavor of my sourdough. There seem to be so many bogus theories about this, that, and the other thing, most of which I tried, and most of which didn't work. I was searching for a clear, straightforward answer, and maybe some clear instructions on a procedure to use, and just couldn't find it. There are apparently lots of books available on the subject, but I'm currently living overseas, and can't just run out and buy one.

A note regarding the ash content of high gluten flours... I must admit that was a guess on my part based on the flours that I have in my region (which also don't specify the ash content), and may not be true of all flours. The all-purpose flour I buy doesn't produce a strong sour flavor, whereas the high gluten flour does.

Again, thank you to all who have responded. It's been a very informative discussion.

You can usually figure out ash content by visiting the web sites of the various manufacturers. If you can't find it on a web site, most manufacturers will answer questions if you call them on the phone or email them.

One thing I haven't found true as I've looked at the specs of various flours is that the ash content of high gluten flours are up around .8%. Most white flours are around 0.5% ash content, regardless of their protein content, as far as I can tell, but maybe I'm misunderstanding Sam's post above.

That's a good reason to mix in some percentage of rye and whole wheat in a dough, or use "high extraction" flour, which is generally higher ash content flour, if you want a more sour loaf. The ash content of a mixture of 20% whole grain flour with 80% white flour should be around 0.7% or a little more. <ash content>=<(.5*80+1.5*20)/100>

First let me say I agree with everything above but one point raises a question. There is no difference between my starter and my dough except the presence of salt. And I use a high, at least by some standards, content of starter in my dough: 600g flour, 450g water, 400g 50% hydration starter, 1 tblsp salt. Now why is it thought that there is no flavor developed in the starter? Tasting the starter counters that idea.

I am not suggesting that a significant amount of flavor comes from the starter, but I don't know that it doesn't. I do know that a stiff starter tends toward sourer flavor and a wet one more mild. That also fits with the comment from bwraith. I am sure this is a little nit-picky at least, but I had to ask.

I ferment for long hours and get my best bread that way, and it is sourest too. For me the two go together. For me, lengthy fermentation with yeast won't make great bread. And then again, I don't know that I have ever done short fermentation with sourdough... or if that's possible.

I think your example shows that the total fermentation time, not just the time the dough itself is fermented, is what you have to focus on to know the total progress of a fermentation.

Here is my way of describing this. Consider two ways of making what will end up being just about the same bread from an acid content or sour flavor perspective.

Both doughs have the same overall formula:

40g storage starter

1000 grams of high ash content flour (high enough to be sour)

700 grams water

20 grams salt

In the first one, just mix up the dough, bulk ferment for 12 hours at 72F (to pick a temperature, and the times to get the same intensity of flavor will vary significantly up or down depending on temperature), and then shape and proof for 4 hours, for a total mix-to-bake time of 16 hours.

In the second, first make an intermediate build with 30% of the flour in the dough (a sourdough preferment to avoid any other terms):

Sourdough Preferment:

40g storage starter

300g high ash content flour

204 g water

Final Dough:

Sourdough Preferment from above

700g high ash content flour

590g water

20g salt

Ferment the sourdough preferment for 7 hours at 72F. Mix the dough and bulk ferment for 5 hours at 72F. Then, do a final proof of 4 hours.

These two breads will be very similar in flavor, texture and whatnot. They have both been fermented for the same total mix-to-bake time, though it was broken up into a preferment and a dough, rather than done as a one-step dough. The second will be a little more fermented, since the salt in the dough slows down the fermentation in the first relative to the second, where for a period of time, there is no salt in the fermentation in the second version.

The point here is that it is the total fermentation progress, not just the dough fermentation progress that counts in the sour flavor developed. A relatively small proportion of the actual acids develop in the preferment - say less than 1/3 of the eventual content, if you just assume that the total acid will be determined by the total amount of buffering capacity of all the flour and that the preferment didn't ripen as much as the proofed dough would by the time you bake. However, the amount of organisms delivered to the dough in the second version is very important. That will have doubled several times over the course of the preferment fermentation, just as it would in the first version over the first hours of the fermentation. Also some of the acid, though not the majority was developed in the preferment. As a result, the dough in the second version can ferment for much less time after it is mixed, because the acids and organisms already were developed in the preferment to the same level they would be in the dough in the second version after the time the preferment was fermented.

So, in both the first version and the second, the total mix-to-bake time from the point the storage starter is mixed with additional flour and water at a given temperature is what is indicative of the sour development.

What SourdoughSam is talking about is getting the instensity of the sour developed. No matter what starter you have, the points he makes are very good regarding how to get more sour flavor.

I would liken it to making coffee. Suppose you make coffee with the French press method. You'll get more coffee flavor per ounce if you put more ground coffee in the pot. Clearly, no matter what coffee you use that will be true. Also, probably you will get more coffee flavor per ounce from a finer grind than a coarser grind of coffee for the same weight of coffee. So, the flavor will be more intense with more finely ground coffee than with less coarsely ground coffee. OK, now please don't beat me up on the fine points of coffee making. This is just an analogy.

Regardless of the methods you use above to fine-tune the intensity of coffee flavor you want, you could also vary the origin of the coffee. Beans from Colombia may have subtle differences in flavor from beans grown in Hawaii or Kenya or wherever. That is a subtle qualitative difference.

To complete the analogy, what Sam is talking about above is how to get more intensity of flavor. I think he's made an excellent point, which is that regardless of the starter, you need more ash content and more time at a given temperature to get more sour flavor. The total acid content is higher if you do those things, no matter which starter you happen to have.

Beyond that, you can get various qualititative differences in the flavor, assuming the same acid content is developed with your starter. Some starters, depending on the organisms and the way they are maintained, and some temperatures and consistencies of dough, may result in the development of more or less acetic acid in the final dough, and maybe the development of some other byproducts in different proportions, as well. Those differences are more qualitative. Two breads may have the same total acid content in them because they were developed to the same total amount of fermentation progress, but they can still have qualitative differences, not from differences in the total acid content developed, but from the relative proportions of various acids that finally develop.

However, before the subtle qualitative differences can be appreciated, you have to do the basic things Sam mentions to get enough acid in the dough to have a flavor effect to begin with.

Someone once asked me what the most important part of making bread was. I thought about it and decided the best answer was, "whatever you're doing wrong." It all counts. Reinhart says that an oven only ads 10% of the final flavor of a bread. Maybe, but an oven sure can detract a lot more than that if it is used badly.

Sourdough has worked, and worked well, for thousands of years. Some people say we've been making bread with sourdough for 6,500 years. Some say 10,000. As a result, it hasn't been a very sexy thing to research. Studies on sourdough don't get grants or commercial funding. In short, not much was done with sourdough between Pasteur and Dr. Sugihara's work in the 50's or 60's.

So, there is a lot of bad information out there. And that is changing. One researcher found that all mature cultures tend to have the same organisms in them, and they are the same ones that are in San Francisco Sourdough. More recent researchers dispute that, having found many more organisms. Some researchers have found that starters, when properly maintained, are quite stable.

And there is the nonsense about metal utensils.

So.... here are some fairly current observations. You can get the same organisms in Milan, New York or San Francisco. Chances favor the organisms coming frim the flour, not the air.

Starters become pretty stable within 30 to 90 days of the time they are started, if they are maintained at room temperature for that time. While I think it's neat that the Carl's 1847 Oregon Trail starter was carried across the country by Carl's many times great grandmother, and i feel like I am touching and tasting a piece of history when I use it, I don't think it is better because it is almost 160 years old. I've gotten as good a results with a starter just a few months old. The age adds romance. And that's not a bad thing.

While sourdough cultures don't contribute flavor the way, lets say, raspbery extract would, they do produce the flavor. When you pour in raspberry extract, the dough tastes like raspberries. Right away.

A very suble difference. If you add starter to dough the addition does not add much flavor. The starter will be diluted and it's addition doesn't materially change things the way adding raspberry extract would. The sourdlugh flavors come about as the starter works on the dough. It's the product of a process.

The stasrter needs time to work. The raspberry extract doesn't.

As to starter types, many bakers will tell you that if you want to duplciate someone's bread, it's better to find out what kind of flour they are using than getting some of their starter. The flour is where lots and lots of the taste comes from. People often talk about how their starter changed when they moved. Studies suggest that it's the same critters it always was. It is hard for stray critters to take over a healthy culture.

However, what an organism eats affects its taste. Hunters prise boars that have been feasting on acorns. French farmers feed their geese special foods to make the goose livers taste better in pate. Many nursing mothers can tell you that their kid gets fussy every time mom eats this food or that. The sourdough starter will change flavor depending on what it is fed. Want a short term example? Start feeding your white flour starter on whole wheat or rye flour. It will change immediately. And far more than the taste of the flour would suggest. Feed it white flour for a while, and it'll calm down again.

Water is an interesting ingredient. If it's potable and not so chlorinated it will kill the starter, it won't impact flavor a lot. However, the mineral content can make a huge difference in the consistency of the dough. I just moved from a hard water to a very soft water area. And the doughs are a lit looser here than there. However, the consistency of the dough does change the acids that the sourdough critters produce. In a firmer dough they produce more acetic acid, in a softer dough they produce more lactic acid. Lactic acid is fairly mild. Acetic acid has more bite.

Thank you for your answers. I do understand that the flavor comes from the fermentation- I did not in any way mean to disagree with that. I thought Sourdoughsam's explaination made perfect sense. It confirmed other articles I've read. Mike, I think you got my point about the starter and flavor. Also, I hadn't thought about the mineral content of the water. Verrryyy interesting.

I'm not much of a scientist, so that part is more difficult for me, but I do understand the romance of using an historical starter. My mother keeps reminding me as I persue this sourdough adventure that I am doing what "Ma Ingalls" did on the Prairie. (Reference: The Little House on the Prairie" books by Laura Ingalls Wilder- a childhood favorite)

Mike,I just wanted to expand on your comment about the difference between starters and the flours you feed them. I've had both my homegrown "Russian" starter and Carl's Oregon Trail starter for several months, and they maintain pronounced differences in smell and taste both in starter form and in the final bread. The Russian starter has a very mild aroma and sharp, clean tang, whereas the Carl's starter has a strongly aromatic buttery-onion aroma and a slightly more moderate tang.

Certainly, the flours that I feed them have a dramatic impact on the aroma and flavor of both starters, and I've fed them several different types. If I feed them certain flours, the differences in aroma and flavors are very pronounced. If I feed them others, the difference is lessened substantially. However, no matter what I feed them, there's a clear, consistent difference in starters.

I agree, of course, that it's not the "age" of the Carl's starter that makes the difference, but the different combination of yeast and bacteria contained in the starter.

I've been through a few different periods using different starters, too, over a few years. I got a number of Sourdough International starters and maintained them for a while. I ended up using the French starter and the SF Sourdough starter for quite a while. They did seem to maintain their marked differences in aroma, at least for the months I maintained them separately. I've also made my own from scratch many times and used a couple of them for relatively long periods. The ones I've started from scratch have all seemed fairly similar to one another and have aromas similar to the SF Sourdough starter from Sourdough International.

Although the various starters do have different aromas, I would say that breads made the same way with different starters are only a little different in flavor, especially if the rise times are adjusted for the slightly different growth rates of each starter. In my experience, whatever very noticeable differences in aromas the different starters have as they mature don't seem to appear as dramatically in the breads themselves.

I was also curious to see whether the differences in starter aromas was reflected in the baked bread, and did some testing in that regard, also. I did three tests (on different days) using identical doughs and fermentation conditions, but with two different starters. I tried fermentation times of 8 hours, 15 hours, and 20 hours. The 8 hour doughs were quite flavorful, but didn't have any noticeable flavor differences between the starters. The 15 hour doughs produced a decisively more sour bread with a distinctive difference in aroma and flavor... quite noticeable, with the Russian starter being mildly aromatic, simple, and sharp, and the Carl's starter having a pronounced onion aroma and more complex flavor (it was almost as though I had baked onion bread, believe it or not). Surprisingly, the 20 hour doughs were quite sour, but only had a very slight difference in aroma and flavor. Still don't quite understand that one, as I was expecting an even greater difference between the starters...

In any case, I've found that different starters under similar conditions can produce distinctive differences in aroma and flavor, but the starters have to be noticeably different to begin with (two of mine aren't) and you really have to draw out the flavor in a long fermentation to get it.

Thanks for all your comments and suggestions! You've obviously been doing this a lot longer than I have, and nothing beats the benefit of experience.

What you say makes sense to me. I've almost always made fairly mild breads until the recent threads here on TFL about sour flavors got me interested in trying to deliberately make more sour breads. In comparing different starters, as mentioned in above, I was probably comparing mild flavored, less fermented breads and simply noticing the less dramatic difference in the mild flavors.

I haven't bothered to spend a lot of time worrying about more sour breads. The few times I had made particularly sour breads, sometimes by accident from a glitch in the schedule or unexpected temperature variations, the flavor was unpleasant to me. However, after all the discussion on this thread a couple of the predecessors about sour flavor, I went and spent some time making successively more fermented breads using the same overall formula. What I've learned is that I was not appreciating enough that there are variations from very mild, to reasonably sour, to unpleasant, and that there is a good middle ground where the sour flavor is more developed but not so intense that it's unpleasant.

I was very pleased with the flavors in the middle range on some of my test loaves that were more sour than my typical recipes have been. Mike Avery's comments about oven spring rang a bell for me, too. I've normally timed my breads to have some oven spring and to be mild, but in doing my various more fermented, more sour test loaves, I had loaves that were proofed longer, had about the same final volume without the ovenspring, but had a more pronounced and very pleasant flavor and a slightly softer crumb - very good.

So, like Lee, I'd like to mention how much I enjoy these discussions and feel like I learned a lot from this thread and a few others recently about sour flavor.

Many people come into sourdough expecting that sourdough bread will taste like cabbage patch kids candy. And that THAT is the taste of sourdough bread.

Part of this comes from what passes for sourdough bread in grocery stores today. When we ran the bakery the most common comment we got was, "Oh, I don't like sourdough!" This was before they had tried any of ours.

Most grocery store "sourdough breads" are not sourdough at all. They are yeasted breads with malic, acetic and fumaric acids added. Basically, some food chemist who has never had real sourdough has decided to emulate it with his chemistry set. And often the results are quite close to the cabbage patch kids experience. It's hard for mere nature to compete with an idiot with a chemistry set. An idiot with a chemistry set that is turning lots of people off to sourdough bread.

The second most common comment was, "But I do like your cinnamon raisin bread!" I never bothered telling them that the Cinnamon Rasin was a sourdough, and that sourdough was responsible for the depth of flavor they were enjoying.

Sourdough has a wide range of flavors from subtle to sour. It's not all one note sour. With many sourdoughs you can still taste the wheat or rye flours and, yes, they are very authentic sourdough breads.

If you want the sour, and there's nothing wrong with that (unless you decide that super sour is the one true sourdough taste), you can get there. Ash content is part of it. However, you can get real sour from lower ash flours. I routinely made very sour bread from All Trumps flour at .54% ash.

While the starter is important, it doesn't matter if you are adding a thick or thin starter to the dough. What is important is the consistency of the dough. When you make your dough, the starter is so diluted the taste it adds by being a component is severely diluited. What is important is the flavor the starter develops while the dough is being developed. A thicker dough is usually more sour. San Francisco Sourdough is usually around 58 to 60% hydration.

Temperature is important and cool rise helps. Craig Ponsford says you can't get a good sour without a long cool rise. However, most home bakers put the dough in their refrigerators which is in the 34 to 38F range. Profesisonal bakers use temperatures in the 45 to 68F range. As a result, there is still measurable activity in the professional's dough, but not in the home baker's dough.

A high temperature can also work. The bacteria and yeast do not respond quite the same to changes in temperature. The bacteria work at low and high temperatures that slow the yeast more. I have a chart that shows this at the bottom of the page at http://www.sourdoughhome.com/risetime.html Sadly, the information I used to put the chart together didn't go to lower temperatures.

While Sourdough sam seems to think there is some conspiracy to keep how to make sour bread secret, it's been on the net a long time. I found the information there. And I also distribute the information at http://www.sourdoughhome.com/sour.html and have for a number of years.

After reading this thread and following most of the links, I'm ready to try a test. Most of my SD breads are mild to very mild and I want to move to what dsnyder calls Wharf Bread. That would be a tangy sour loaf.

My summary of the above indicates that a 58% hydration mix using 80% Harvest King and 20% medium rye in a single stage ferment, inoculated with 40 grams of active starter should produce a sour flavor if fermented at 80 F for 15-24 hours. I'll start it now and report back tomorrow.

This will be a departure from my normal procedure in that I usually use 65-70% hydration and I generally use a much smaller percent of rye. 1 Tablespoon of rye in a 600 g batch to improve the flavor.

Just something to consider - I would suggest you try using 5% rye and 15-20% Golden Buffalo or whole wheat, trying to avoid complications associated with the rye's effect on the gluten in the dough while doing the test. I assume you are trying to raise the ash content of the flour with the addition of the medium rye. You can get the added ash with whole wheat or high extraction flour like the Golden Buffalo you sometimes use - don't know if you have any on hand, though.

I tried a taste test somewhat similar to what you're suggesting, and I went a little too stiff the first time. I suspect that, considering the rye, GB, or WW flours will absorb more water, that 58% hydration may be going a little too far on the stiffness of the dough. I did a test similar to what you describe, and ended up with a dough that just wouldn't rise well and became way too sour after a very long fermentation. Just a tiny bit more water, like maybe 62-64% hydration will probably be stiff enough to get plenty of sour flavor but with a better rise.

Also, I don't know how big of a dough you're doing. My calculations, admittedly with my particular starter, and starters vary as we all know, are that for 40g of starter in 1kg of total flour, you would only need about 13-14 hours of mix-to-bake time at 80F to get a reasonably sour loaf - maybe 9.5 hours bulk and 3.5 hours proof. The amount of time needed to get to the same amount of sour at 70F would be 22 hours mix-to-bake - 16 bulk, 6 final proof, so it's a lot less at 80F.

Good luck with whatever you end up trying. I'll be interested to hear, since I've been trying various things myself.

I've noticed that when discussing sourdough flavour, factors etc. - there seems to be a focus on the ingredients for the builds and final dough and/or rise times, temperatures etc....rather than the 'mother' starter itself.

Is it possible that this might be a really important factor? Afterall, we know that different strains of lactobacillus and yeast develop under different conditions (food source during the initial stage of cultivating your starter as well as feeding regime) - not to mention different ways they metabolize sugars and perform under a given set of environmental factors.

Might this explain why different people following largely the same recipe/strategy obtain different results? I know that I have observed, on occasion, the apparent opposite of the intended effect when I try to follow advice which clearly works for another person's starter....

As I've mentioned in another post - I've been having really quite moderate rise times and a variety of different build strategies and temperatures - and I've consistently been getting overly-sour (in my opinion) results with what appears to be a damaged gluten structure (protease perhaps?)

I think one of the problems is that all kinds of seemingly insignificant factors in the process of making bread will change the results in unexpected ways. It is hard to make sure all the factors are really the same from one kitchen to another, even with a very detailed post describing a recipe. Most times I read "I did exactly what was specified and got a different result", the statement isn't very useful because most of the key details were omitted. After looking in more detail, I hazard to say it will much more often be the case that something was different in the processing, not some big difference in the storage starter itself.

My experience is that when you control for all the many different factors that affect the way a bread comes out, the type of starter is not as significant in the results as other process parameters, especially the following:

Whether the starter is healthy and active or not, regardless of the type or whether it is maintained firm or liquid and whatnot. So many problems relate to a poor starter maintenance method.

The selection of flours in the overall formula (high or low protein, high or low ash content, amount of bran in the flour, how much rye, how much spelt, and so on).

The hydration in the overall formula (stiff, soft, or very slack dough)

The time and temperature of the various rises. (very fully proofed, or not)

The use of autolyse or soaks (can have a big effect on gluten quality, and also can make a big difference in the amount enzyme action on the flour)

The success of the kneading and folding (big effect on gluten development)

Sure, some starters naturally create differently flavored doughs than others, including possibly more inherently sour flavors, all other things equal, either because of a difference in maintenance strategy or because of the particular types of organisms that have established themselves in the culture. However, I would say it is not as big of an effect as the process factors, especially when you adjust for the fact that one of the reasons one starter can be different from another is that it ferments a little faster or slower. That can be adjusted for in the time and temperatures used in the various rises. After you adjust for that, the starters are even less different from one to another.

Yes I agree - the "I did exactly what was specified and got a different result" often doesn't account for the seemingly small but possibly significant differences between a recipe and it's execution.

What's troubling me is that I've noticed in my own sourdough an overall trend which does not seem to be tied to flour type, starter-to-final-ingredients ratio, temperature or hydration. I observe the same breakdown with a basic white 60% hydration direct dough and a 100% WW 70% hydration dough with intermediate build. I guess I'll have to have a careful rethink about any other common process factors.

I keep thinking something bad is happening to the gluten during proofing because it certainly seems fine prior to first bulk ferment....but I guess I need to try several different folding techniques/strategies and compare results before I draw any conclusions or start pointing the finger at the bacteria/yeast.

What you describe does make me wonder what might be going on. However, maybe it's better to start a new thread or blog entry, if you feel like getting into it more.

Probably the first thing is to verify the starter itself is behaving, which means going over the feeding routine and maybe comparing how long it takes to rise by double for a given feeding at a given temperature. A problem with the starter could cause the issues you mention.

Then the details of one of the bread recipes you feel isn't doing what it should could be discussed.

Usually something will pop out. This might not be it at all, but one thing I've noticed is sometimes this type of problem is related to the change of season. This time of year, kitchens are beginning to warm up, so feeding routines that used to work but were on the edge of underfeeding are more than underfeeding at warm temperatures. Recipes that used to work but were on the verge of overproofed become way overproofed.

Since I am a Novice to all this I am learning from everyone's comments. However I would like to suggest that since different people are finding different options that work for them, it is possible that the sour taste is different to different people. What is a strong sour taste for some can be very weak for others.

For instance:

My wife and her father have a Very sensitive palate that can pick up incredible subtleties of taste.

I appreciate all of this expertise being flung around. I seldom pay much attention to this kind of discussion because I like what I make. That is too bad. I think I understand this all a lot better. I am inspired to try other things again. I haven't thought of adding rye or ww in small amounts to add flavors and flavor textures lately. Frankly, making bread that exceeds store bread by such light years was enough for a long time. Now it's time to see what else there is.

I make my family's daily bread each weekend and have been slow to vary from it. I make sourdough, ww sandwich, and a really sour rye. I think this weekend I will get loose with the imagination. Thanks for vaulting me out of my hole. I know I am safe if I fail miserably with attempts at new things because I can always go back.

Not unlike others, I make my bread by 'feel', and the feel has everything to do with my mood and NOTHING to do with my choice of flour or any learned trick. I simply go with the flow of the day. BUT, as many will tell you, when someone comments about your bread and respectfully asks for the recipe, it can prove daunting and almost futile to offer up an answer. This occured again this weekend when I had family visiting for the TMS race events. I sent my sister packing homeward with a loaf and politely asked her to 'forgive' me if it wasn't my best. It came from the freezer and heaven only knows what it's flour content was. She would later tell me that she and my brother-in-law had devoured the loaf and asked if I would please send the recipe. I couldn't help her much, if any, and then today she received her first KA catalog. She's plotting all things, 'flour,' and has begun a list of items she feels she must have. Now I must turn her attention toward, TFL.

Again, you wonderful group of souls have saved the day! I really wasn't trying to ignore her request, I simply couldn't offer her a realistic one via email or telephone. Much of our success comes from not only feeding our tummies, but our souls. I learn more and more each time I visit. This thread helps shed light at the most important time, development. Each loaf is a journey.

Just for fun, I went and got myself some sodium hydroxide, intending to measure the acid content in my starters and doughs.

Attepting to summarize a complex and technical topic:

pH is a measure of the concentration of free hydrogen ions in water, which is a measure of whether a solution is acidic or basic. The pH of pure water is 7, called a "neutral" pH, i.e. neither acidic nor basic. pH can range from 0 to 14. A very acidic solution, like lemon juice has a pH around 2. More mild solutions have a pH around 3-4, like wine, OJ, and ripe sourdough starter. Bases make the pH go above 7. For example, I mixed 4 grams of sodium hydroxide, a strong base, in 1 liter of distilled water, and the pH is 13.

The concentration of total acid in a solution is not the same as the pH. A small amount of an acid in pure water can make the pH drop way down to 1 or 2 very quickly. However, if the water is "buffered" with other chemicals that resist the change in pH, then the concentration of acid has to be higher before the pH drops. Flour has natural ingredients that act as buffers. You can build up more acid without reducing the pH in a mixture of flour and water than you can in pure water.

In particular, the higher ash content of a flour, the more buffering the flour provides, the more acid it can build up without the pH dropping below 4, where the Lactobacillus begin to be inhibited and gluten begins to break down more quickly.

Why measure the total acid concentration in a dough, not just the pH? From what I've read, it is suggested that the intensity of sour flavor is more related to the total amount of acid than to the pH itself. So, total acid content, not just pH, is an interesting thing to measure and try to manipulate with flour choice, fermentation time and temperature, or hydration, to control the amount of sour flavor.

You can measure the total acid content by finding how much sodium hydroxide solution it takes to neutralize the acidity in a starter or dough, as described below.

I did the following quick tests. I took my starter and fed it 5:20:25 with white AP flour (ash content around .5%) and let it get fairly ripe. I then took 15g of the ripe starter, mixed with 100g of distilled water in a small plastic jar, and measured the pH to be 3.6. I then slowly added my solution of sodium hydroxide (0.1 molar, i.e. 4g of crystals/liter of distilled water) until the pH rose to 6.6. It took about 9.5 ml.

By the way, this procedure for measuring "total titratable acidity" (TTA) is explained in an American Institute of Baking article (May 1989) and is extensively quoted all over the place on the internet.

I then did the very same thing as above, but I fed my starter with Golden Buffalo (ash content around 1.1%) flour instead of white flour. The pH was also 3.6, but it took 16 grams of sodium hydroxide to bring the pH to 6.6. This shows that the Golden Buffalo flour with higher ash content had more total acid at the same final pH after becoming mature than was the case when the starter was fed with white flour.

I'll be doing some more tests monitoring the acid content for a few different choices of fermentation, hydration, and flour using the total acidity measured by how much sodium hydroxide it takes to neutralize the acid. I'll eventually, whenever I finally get around to doing all this, write a blog entry describing whatever results I get.

Sorry, I know this was lengthy and probably too technical, but I think it helps explain why ash content is important to sour flavor and is mentioned all the time by sourdough experts, at least the scientific sourdough geeks.

to provide this sort of technical data. One question though, you said the first test took 9.5 ml of sodium hydroxide and the second took 16 grams. You probably intended to provide similar measuring units for each...?

Yes, I made a mistake mentioning the units. In both cases I weighed the amount of sodium hydroxide that was needed to neutralize the acid, so it should read 9.5 grams of sodium hydroxide solution, which will be very close to 9.5 ml of solution, since the water is fairly close to 1 gram/ml.

The more typical way to do this procedure in the lab would be with a "buret", basically a thin, long graduated cylinder with a stopcock at the bottom that can "titrate" or dribble in the sodium hydroxide solution, while you stir the sample and wait for the pH to adjust to the "end point" or target pH, in this case 6.6. Then, you close the stopcock and measure the amount of sodium hydroxide solution that was required to get to a pH of 6.6 by checking the change in volume by viewing the markings on the buret to see how much the solution dropped.

So, the typical way of quoting the results would be something like:

9.5 ml of 0.1N sodium hydroxide solution for 15g sample in 100 ml of DI water to a 6.6 pH endpoint.

The 0.1 N mentioned above is the concentration of the solution in moles of free hydroxide ions/liter, which in this case is accomplished by dissolving 4 grams (0.1 moles) of sodium hydroxide crystals in distilled water so you have 4g of Sodium Hydroxide or "NaOH" per liter of solution.

However, since I don't yet (yet...) have a buret, I made a mixture using my scale (precision is 0.1g, and Escali lab scale) of 15g starter with 100g of distilled water. Then, I further used the scale to weigh the added sodium hydroxide solution, stirring, trying not to change the wetness on the stirrer or the pH meter, which would change the weight. I practiced, and it seemed like I was getting the same weight if I stirred or measured pH and removed the stirrer and pH meter each time. Bottom line, I'm looking for a buret before I do any more of this testing. It will make things far, far easier.

I always thought (from my high school chemistry classes) that combining acids with bases caused a chemical reaction which destroyed them both and left salt in their place. So, I thought that there was no increase in acidity of the dough until the buffering capacity was used up, as the acids produced were being destroyed by the alkaline minerals.

If I understand you correctly, you are saying that that's true only of free ions, and that there's some portion of the acids and bases that don't combine with each other, and that, therefore the total acidity does increase even while the buffering capacity is not used up. Is that right? This is not an area in which I have the slightest expertise, so I'll have to do some reading up on it to understand it.

Yikes, I don't want to get into a whole discussion of acid base equilibrium theory for strong vs. weak acids and bases and why buffers work and all that. I don't know enough to shed much light on the subject, anyway. So, rather than go on about that and cluttering up this thread any further, I'll just try to explain my motivation for measuring total titratable acidity (TTA) and call it quits before it's too late.

For me, regardless of how well I end up understanding the underlying chemistry details, what's interesting is that you can easily measure the pH and the TTA (total titratable acid) with the procedure mentioned above. The pH should indicate when the fermentation is coming to an end because of the inhibitory effect of low pH on Lactobacillus bacteria. The TTA tells you something about the build up of total acid and is related to the strength of the sour flavor of the bread. It seems like it should be a measure of how much total fermentation has occured at the point you measure it.

Like many things I do related to this bread hobby (e.g. a milling operation in my basement workshop), measuring pH and TTA for a bunch of test doughs will be a lot of work for unclear gain, but if I'm lucky it will be fun and I will have learned something after I'm done.

A base will neutralize an acid to form a salt and water. With appropriate amounts and strengths, there will be no more acid.

A given weak acid will ionize in water, lowering the pH. For the given acid, there are certain salts or minerals (buffers) that cause the acid to ionize less, thus the pH is lowered less. If there’s enough buffering material, there could be plenty of acid; but the pH would be higher than in a simple solution of the acid in pure water.

Thanks for the explanation. Do you happen to know what compounds are in flour that perform the buffering? I've been trying to read and find out, and so far I haven't found any lists of the buffering salts or minerals in flour.

Could it make sense to add buffers to artificially raise the buffering capacity of a flour? I'm wondering if there are buffering compounds (tasteless and safe) that would allow you to do that.

Beyond acetic acid and lactic acid, I don’t know what other acids might be present in significant quantities in dough. Both yeast and bacteria produce various acids in fermentation. Specific identification of acids would be necessary to identify any buffers.

Without research, I don’t know what buffering agents might be in dough.

From a brief look at the web, the following compounds are added to some foods: sodium acetate, potassium lactate, sodium lactate, and calcium lactate. I think they would buffer the aforementioned acids.

Thanks, Charbono. I'll do some more reading up on the difference between neutralizing and buffering.

That clearly answers one of the things that didn't make sense to me about buffering capacity. I was working under the mistaken assumption that the acids were being neutralized, which didn't mesh logically with increased sourness in the dough.

Are you saying that the total acid content and thus the sour would be higher using WW or the Golden Buffalo even if the time were the same as another batch using AP?

I thought the higher ash meant that the dough would tolerate a lower PH before degrading the dough. Further both mixes would acidify at pretty much the same rate but the higher ash content would allow you to ferment longer without damage. Yes?

The total acidity can reach a higher number at a given pH in a higher ash flour because the fermentation can progress further (more fermentation products, i.e. total acid, more growth of the culture, and so on) before the pH drops because of the greater buffering capacity of the higher ash flour.

How long it will take for the fermentation to progress to the same pH could be a complicated question. Your basic point that the higher ash flour should take longer makes sense. However, I'm not sure it's a good assumption that the fermentation rate is the same for a high ash and low ash flour.

I've seen that whole wheat and other high ash flours like GB ferment more quickly than white flours. So, it's not clear to me whether you have to run a high ash flour fermentation longer, all other things equal, to reach a given pH. That's one of the interesting things I'd like to test, now that I've decided to do a bunch of pH and TTA measuring on some test doughs and starters.

What I think is true, that I think you are also saying, is that it should be case that when the dough does reach that pH of around 4 when the dough fermentation slows and overproofing is an issue, however long that may take, the flour with the higher ash content should have higher total acid content than the flour with the lower ash content.

Just as I said I was going to start a test mix yesterday I was dragged away to a pressing emergency so I didn't get to start my tests until today. As per your suggestion and understanding of my reasoning Bill, yes I was adding rye to raise the ash of the mix. So I have 2 batches going now. One is 480 g Harvest King and 120 g medium rye at 58% and the second which is 5 hours behind the first is 200 g of Golden Buffalo, 50 g WW and 350 g of Harvest King.

The second batch weighed in at 1074 grams after mixing which means I added 74 g of additional water when it looked so dry. So that's 70% hydration. I probably over did the water slightly but the two batches feel similar at this point. Both are sitting in an 85 F environment above the refrigerator. My goal here is to make a sourdough that is at the extreme end of the range and learn to back off to the perfect Wharf Bread".

Both mixes window paned well in the DLX and I plan to bake them at 15 hours after mix.

Bill if your fermenting chart says this time isn't right let me know asap so I can make adjustments.

I'm kind of in new territory trying to guess a more fermented rise time like this, especially at the warm temperatures, but I would say the mix-to-bake ought to be more like 11-12 hours, maybe 7.5 bulk ferment and 4 proof if all of it is done at 85F, and this is assuming you used 40g of 100% hydration storage starter in 600g blended GB and white flour as you describe. The really extreme version I did would've been out around 15-16 hours at that temperature, but it was unpleasantly sour, and I doubt at 70% hydration it would work. The extreme one I did was down less than 60% hydration, and it came out kind of dense. The more reasonable one I did was plenty sour, but had a hydration a little less than yours and would've run more like the 11.5 hours mix-to-bake.

As a reference point, I would've expected that at these temperatures it would double in around 7 hours, but that's undisturbed, so adjust your guess accordingly if you are folding and therefore possibly deflating the dough.

Good luck. I'll be very interested to hear how these come out for you. By the way, I've noticed these very sour loaves taste much better a couple of days later, even if they were overly sour at first.

Bill

PS, I ran what I would typically do in the past to get a very mild loaf with more oven spring, and that would only run about 8 hours mix-to-bake at 85F. I'm more sure of that number being right at the low end. So, at a warm temperature like 85F, it could well make sense that a very sour loaf would result from 11-12 hours fermentation.

I'm also following your experiment with interest. Let us know how it turns out.

All of my experimentation to date on increasing sourness has been done on doughs with 50% to 60% hydration (although I've made other breads with higher hydrations... just didn't try to make them sour). My experience with high gluten, low hydration doughs is that there's a ton of flexibilty in fermentation times before the dough structure collapses. I recently did a fermentation for 20 hours at 28C, which was far, far longer than I would have thought possible. The bread didn't get any more sour than my 12-15 hour experiments, but I'm certain that's because the buffering capacity of my dough ran out. Similar to Bill's experiences, there was less oven spring (still some, amazingly enough) but a fully risen dough, nevertheless.

I'll be very interested to know how this works for higher hydration doughs.

The results of your experiment would seem to provide a physical basis for what has been, thus far, a perceived difference in flavors in white sourdough breads and whole wheat sourdough breads that I have made. The only sourdough breads that I have made so far that were so sour as to be unpleasant have been whole wheat breads. There have been some white breads that were tangy, but none of them have approached the out-and-out sourness of a couple of batches of whole wheat breads.

If whole-grain (more accurately, high-ash) breads are able to deliver a higher acid load than white breads, it would follow that they would be more sour. So, if I want to make breads with a high percentage of whole flours, I need to adjust my process to facilitate a faster fermentation to produce a bread that is, to my tastes, not so overwhelmingly sour.

Your findings also explain why breads made with a small percentage of whole grain flours are, generally, more flavorful than breads made with all white flour.

Thanks for running this test. It gives me some insight on how to handle things so that I get the kind of flavors I want in breads with differing types of flour.

Most of my accidentally too sour breads were WW breads, too. However, as I was mentioning to SourdoughSam, I've mostly been making higher hydration breads and leaning shorter on the fermentations, particularly with WW breads. As a result, I've had mild sourdough flavor that I find very good - for me much preferable to yeast breads. I think it's a little easier to get a nice open crumb following that process too.

However, As we've had these various discussions, I've tried to deliberately make sour breads by running longer fermentations on stiff doughs using high ash, high gluten flours (e.g. 50/50 blend of Heartland Mill Golden Buffalo and High Gluten Bread Flour). I've learned you can let a stiff dough proof longer, get good loaf volume without much oven spring, and get more intense flavors. Now I'm hoping to learn how to fine tune hydration and fermentation times (which will vary greatly depending on the temperature used) to get a desired amount of flavor, rather than going too far and getting unpleasant sour flavors and problems with collapsing loaves.

There's clearly more to taste than pH. The different flours you all are using - white, high extraction, WW, rye - each lend a taste to the bread. What makes bread taste good is, as I see it, the particular complex tastes as they compliment each other. So how pleasing more or less sourness is depends on the rest of the flavor mix. And "pleasing" depends on the preferences of the individual.

Individual preferences notwithstanding, I wonder if some flour combinations are more pleasing to most when the bread is more sour. I also wonder if the rest of the flavor profile influence the subjective perception of sourness. I also wonder if the perception of sourness has a constant relationship with pH or is also influenced by the other flavors present in the bread.

I hope this makes sense. I've been thinking about comments a while back in other threads about some really disliking intense sourness in 100% WW breads, even if they might enjoy it in other breads.

I agree completely that there are lots of subjective factors. I'm sure that the overall progress of the fermentation, the flour choice, the amount of salt, any other ingredients in the bread, even how moist the crumb is from the length of the bake, the crust, and so on and on all combine to have an overall effect that may be pleasant or not. The sour part is definitely a component, not the be all, end all.

One great example of that for me is sourdough raisin focaccia. I think it may be the favorite bread around my house. No one has ever said much other than, "I love this bread", and when friends have tried it, sometimes the responses are involuntarily sensual, "Ooh, yes..., YES, GIVE ME SOME MORE OF THAT!" Anyway, I think it's the raisins combined with the sour combined with a tiny bit of salt sprinkled on top. The combination is just one of those really good things. I do ferment it long enough to get a more intense sour flavor, and I do add a very small amount of rye and whole wheat to it, too. If you took away any one of those three factors, salt, raisins, strong sour flavor, it just wouldn't be the same at all.

I suspect part of the reason you get more of the "I don't like the sour in WW breads" is just that it's so much easier to get to the unpleasant end of the sour spectrum with them. If you do one of the standard approaches to making good WW bread, which would be to soak the grains and make a somewhat wetter dough, it will ferment faster than a typical white flour dough. So, it's natural if you're used to the timing in whiter breads, that you would get a more fermented dough. Then, the WW flour has three times the ash content of a typical white flour, so the acid load can be far higher for a bread fermented to the same pH, and you end up with a far more sour bread, possibly unpleasantly sour.

On the other hand, I've noticed a tendency for that unpleasant sour of WW to happen more in red wheat than white wheat for some reason. I tend to put spelt, rye, or white wheat in my levains for that reason. Something about heavily fermenting red whole wheat flour leads to an unpleasant sour. Of course, that's just for my taste, not a general statement, but it goes to your point about subtle flour differences and individual preferences, and other factors combining to make one bread different from another, although fermented very similarly.

So, all told, it seems to me the general amount of total sour is determined by the total amount of fermentation progress you can get with the ash content, flour choice, dough consistency, and all that. Then, there are lots of other factors in combination, including individual tastes, that result in the taste experience itself.

Having said that, if you go back to the question of how to develop the sour flavor component and control it, I feel Sourdough Sam's original post and this thread address the issue better than a lot of other things I've read on the subject.

I baked the first batch after 15 hours plus an 1-1/2 hour proof. This was a batch that consisted of a total of 600 gt of flours (480 g Harvest King and 120 g medium rye), 348 g water (80 F) and 12 g salt and 40 g starter (100% hydration). I mixed/kneaded for 10 minutes on first speed in the DLX using the hook. My IR thermometer said the dough mass was 74 F. I shaped into a ball and placed in an oiled bowl and covered with a plastic bag above the refrigerator where it is 85 F.

At 15 hours I gently tipped it out onto the work surface and pulled the edges in kaiser roll style and formed a boule. Placed on a parchment paper and covered with a tea towel it rose perhaps 50% in 1.5 hours whereupon I slashed and slashed and slashed until I was sure I had overdone it. Baked on a preheated stone at 450 F for 35 minutes with standard steam. (temp was lowered to 400 after 20 minutes due browning).

You can see that the crumb isn't as airy as I would have hoped for but the proof time was shorter than usual and cooler than I like.

I could smell a distinct sour aroma when it finished ferment and I was excited for the difference. The finished bread wasn't overly sour but more so than I have made in the past. The flavor is what I would call very good sourdough and I suspect that it would have been better had the proof been longer. This loaf was hard to get to temperature because of how dense it was.

My final word on this is that the premise set forward by the learnid breadsmiths above does work. A stiff dough fermented for a long time at room or higher temps. will create a nice sour crumb. I'm very happy that this was successful as I can now tune the flavor by adjusting the hydration and bulk ferment conditions.

The second batch is out of the oven and I'll post that when it cools enough to slice. On this batch I followed Bills suggestion and used Golden Buffalo and a small amount of WW along with the HK.

Glad it worked out. I'm surprised that the loaf will sustain that long of a fermentation, but I guess the rye and the flour you're using must be stiff enough to be more like my stiffer earlier attempt. I would've thought that at 70% hydration, even though it's fairly stiff, it wouldn't be stiff enough to run the fermentation that long. It's so hard to compare these things from afar.

One mitigating factor is that it started at 74F, and maybe your starter doesn't ferment quite as fast a mine or the flour blend ferments a little more slowly than I was guessing with 20% rye/80% white flour. I did a simulation on my rise time model starting at 74F and adjusting the temperature up to 85F over a period of a few hours, then letting it stay at 85F. The result was that it would be more sour than my second more hydrated somewhat shorter fermentation attempt but not quite as sour, but close, as the one I felt was extremely sour that I did first.

I would think the one with GB flour will ferment more quickly if you follow the same procedure. If I use the same temperature pattern as above but increase the fermentation speed by 10% or so, as I think would be the case with the 50/50 GB/HG blend, like my tests that used 50/50 Heartland Mill GB/HG, my models would say it should come out about as sour as my more extreme test.

I'm not sure what the ash content of medium rye is, but if it's something like 1%, then you would think the ash content of the batch with more GB, also at about 1% ash content, should be higher overall for that batch, since the percentage of GB is higher than the percentage of rye. That might allow it to reach a higher acid content, depending on how long you run the fermentation.

One thing to consider. I wonder if it would help to do the shaping earlier. I think the loaf might get to a higher volume if allowed to proof for more like 3-5 hours, and the shaping could be done more easily, if you do it earlier before it has fermented as much. On the other hand, maybe a very gentle shaping without deflation along the lines of a ciabatta works just as well.

What do you think the effect on the gluten is for the rye vs. using GB? I'm not sure, as I don't do any real rye breads. I've only done about a max of 10% rye in my breads, although I frequently put something 5% whole rye in my breads, usually in a levain.

The dough felt strange to my hands after a long ferment. I have had high percentage ww and rye mixes go to rags when I left them in ferment to long. Just before they fail the dough gets sort of plastic feeling and not very sticky. That's a little of what I was getting with these. In both cases the gluten didn't feel like it was still strong after fermenting. Shaping a Boule was possible but I couldn't really get a ball, only a thick disk and the bottom folds didn't want to connect well so I had to pinch them. I hope that made sense.

Another thing is you suggested 20% GB and I used 33% so my overall high extraction percentage was quite a bit higher.

I'll do another batch after I refresh my starter and pay attention to the blend better. I do like the GB, very flavorful stuff.

What you describe definitely makes me want to suggest shaping a few hours earlier. If you do a 16 hour mix-to-bake, maybe try shaping at 11 hours plus or minus. I broke it up that way with my sour tests, and it worked fine for me. The dough was easy to shape 5 hours before the bake (no stickiness or preliminary signs of going to rags), and the loaves seemed OK after 5 hours, taking slashes and all that. As long as the total mix-to-bake time is the same, it should develop about the same flavor either way.

Congratulations! I'm very pleased to hear that this worked so well (you hate to give advice and have it turn out to be a miserable failure!). I had a sort of "Eureka!" feeling when I finally got that sourdough zing the first time. Of course, I don't always bake sour sourdough, but knowing how to do it gives me a much greater feeling of control over the flavor.

I suppose I should have mentioned that I don't shape the loaves at all after such a long ferment. I simply scrape them from the bowl very gently, which slightly deflates them, slash them, and bake them "as is." If you're making a boule, this seems to work fine (see attached picture of some loaves I made a couple of weeks ago using this method). If you're going to shape them, I agree with Bill that that should probably be done earlier in the fermentation, before the dough gets really soft and airy.

SourdoughSam,I must admit I was somewhat skeptical about your suggestion. It seems so simple and so close to what I have been doing but the results are clear. With knowledge about ash content and buffering I think anyone can find a time and temperature together with a hydration level to use with your favorite blend of flours that will make a perfect sour.

Thanks Sam and Bill and Mike and the others who understand the science of fermenting for sharing and contributing to this thread.

This is the second test batch in my attempt to make a very sour loaf of Wharf Bread. The first test was a dry 58% hydration mix and this is 70% but used a blend of high extraction flours that were more thirsty than the first. The specifics are:200 g Golden Buffalo, 50 g WW and 350 g of Harvest King. 40 g starter at 100% hydration and 12 g salt. I started with 367 g water at 80 F and added an additional 55 g of water on condition. The two batches had a similar feel in terms of tackiness. Both were handled in similar a manner except that this batch was proofed in the microwave with a cup of previously boiling water to keep the humidity and temperature up. Proofing time was again 1.5 hours.

You can see in the crumb photo that the dough was expanding evenly and is more even and airy. In both cases the evidence of oven spring is in the slash pattern.

The tasting is a tough job but someone must do the hard work. Wanting to lead by example, I am enjoying the first slice of a still barely warm SD loaf. To be honest I don't think it is as sour as Test #1. The mix of flours is different and therefore the ash content.

If I understand the discussion of acid buffering above I think what happened is that the higher ash content of the GB and WW tolerated the souring process better (fermenting and lowering of the pH) and therefore didn't exhibit the same sourness as the first batch. It could be that both loaves will sour-up some as they age over the next few days. (The likelihood of this bread surviving even today is low unless I take security steps)

The lesson learned here for me is that the higher ash content could have been fermented longer for a more well developed sour flavor. The higher hydration definitely helped the crumb and open structure although it could stand to be larger with longer proofing. So, the formula is higher ash=longer ferment or warmer temps for the same sour.

Please, Bill if you see something here that isn't right by your experiences, point it out. I am happy that I have finally found a reliable way to takes steps toward building a better sour loaf.EricSour Test #2Test #2 Crumb

The thing that still surprises me is that it was OK to ferment this loaf for so long, up at 70% hydration, once again. This time, it's a blend I'm fairly familiar with, so I have a better feel for what the 70% hydration may be like in terms of dough consistency. I understand the GB is very thirsty, but 70% isn't as stiff as even my second version. The second version I did that was less sour than the extreme one I did but still sour enough, was at 66% hydration and 50/50 GB/HGB, so I guess it could have been fermented for quite a lot longer, based on what you just did. Although I built it differently, the timing I used probably would be the equivalent of about 2 hours less fermenting than what you did here. The crumb of my second version was far better than the first version at 58% hydration, but I would say it was more dense than yours.

So, it all seems to boil down to doing enough of these to discover where the hydration gives a nice crumb, while at the same time, you can still run the fermentation long enough to get the amount of sour desired. In my rise time models, I don't have anywhere near as good a feel yet with these stiffer doughs for how long I can ferment before they break down. With wetter doughs, there is a fairly consistent indication in my models for about the limit on how long the fermentation can run, but clearly, there is a lot more flexibility than I thought with these lower hydration doughs. It's just going to take adjusting the hydration upward and really letting the test go a long time a few times to get a better feel for it.

Thanks for doing this test and posting it. At some point, I'm going to try a similar recipe to yours that will be up at 70% hydration and fermented longer. Hopefully, I can get a bigger loaf volume. The sour flavor already seemed plenty in my second version, if not too much. I think you like more sour than I do, which isn't too surprising. I definitely have a preference for milder sourdoughs. However, as you say, then it's a matter of playing with hydration and timing to get the desired flavor.

I read yesterday on this site that pineapple juice mixed with rye flour will keep the ph low and possibly bypass the gas producing bacteria which it says can raise the starter to three times its volume in a relatively short time. (SourdoLady) I have been having this happen with my Sourdoughs International starter, and the other rye and water starter I tried. The dough would rise fairly quickly even at lower temps. Seemed the bread would peak before having time to develop flavor. When I put the rising loaves in a cooler with blue ice, lengthening fermentation time by lowering the temp, they still didn't develop much flavor.

Perhaps increasing the ash content, since I had been using just unbleached white flour in the bread, will make a difference.

I followed Sourdolady's procedure and had good results. I had trouble at first because my house was too cold. I read about this method in the Los Angeles Times food section about 2-3 months ago and then saw her steps here too. The LA Times writer tried a few methods, reviewed them, and preferred the juice starter. I used rye and pineapple juice and have switched it to white/white whole wheat.

I think though, that the starter and the juice's effect will be minimal. There has been a lot of discussion here about fermentation and flavor. You might want to read around the site bit. Good luck.

Thanks, Marni. It is beginning to dawn on me...that it's not so much the starter but the fermentation of the actual dough that makes the bread flavor. I tried the No Knead bread yesterday and was pleasantly shocked at the crust and crumb that developed so easily using such a simple technique, requiring just 1/4 tsp dry yeast. I'm thinking that if I use some higher ash flour with this method, I just might get some sourness, too.

After thinking about Bills suggestion to shape earlier and SourdoughSam's mention of not shaping at all, I decided to try another method. My first 2 trials were very flavorful soon after baking and both felt a little too dense. The first at 58% was very dense. The lower hydration was working to improve the sour flavor but the crumb was heavy. So I decided to raise the hydration by 3% to 61 % and shape the loaf after 12 hours while folding and strengthening the gluten and then place the dough into a plastic Banneton for the final 3 hour fermentation/proof.

Mix together in a bowl with a spoon making sure to get everything incorporated well. No Kneading or mixer involved. Cover and place in a warm 85 F space and leave to ferment for 12 hours.

Tip out onto the work surface and spread dough to large square and stretch and fold. Knead for a few seconds by French Fold, Shape and establish tension and place in banneton for final 3 hour ferment time. Bake as usual.

Interestingly the mix had a nice feel at 12 hourd and the gluten tightened up very well. It popped out of the Banetton easily and you can see the results below.As for the sour flavor, I would say it was about right for me. I'm trying to make a loaf that is too sour so I can back off to perfect. I'm starting to think the ash content might be to high, holding back the sour flavor.

Those loaves look really good. If you're able to ferment them that long at that temp, get the good sour, and have a crumb like that, I'd say it's darn close to the intended target. I'll be curious to see where you go next with it. Thanks again for doing (and posting) all these tests. You're saving me a bunch of test baking, as I know these flours and have a very good sense of what you did from your explanation.

I'm encouraged that the dough was in such good shape after 12 hours. It felt a little loose while shaping, especially considering it was 62% hydration. I'm still not getting those larger holes you see in SF Sourdough but it's a darn good sandwich style crumb. My wife and 15 yo daughter both gave the thumbs up on this last batch. I still haven't been able to go to far into the sour taste where they don't like it.

Today I'm dropping the GB and raising the WW to 10%, everything else the same. That should be lowering the total ash of the flour mix. I think I'll come down 1 more percent on the hydration too. I'd like to still be able to handle the dough after 12 hours. Small changes seem to have a noticeable effect.

I know that I'm going to just figure this out and a big warm front will come through we'll be into summer temps and I'll have to start over lol!

Sourdoughsam:What was the crumb like in those small boules you posted? The process you talk about seems like it's getting like a ciabatta method. I'm thinking the even crumb I got in this last batch is from not having a well developed gluten structure earlier enough in the ferment. The structure is allowing the gas to penetrate and escape. Maybe if I folded or kneaded lightly earlier those co2 pockets would stay trapped.

I'm with Bill on this one. I think the crumb of your latest batch looks pretty darned good. Not much room for improvement, there.

The crumb of my small boules wasn't great, probably somewhere between your first and second test runs, but crumb was really a secondary issue to coming up with a reliable method for controlling flavor.

I was actually thinking of trying your kneading and shaping method for my next batch! ;)

Last night I baked another in a series of sourdough breads in an attempt to uncover a method for improving the sour flavor by changing the flour mix and using a standard 15 hours for the ferment time.

To be fair, I am making some very nice bread with this series. My wife and teen daughter are loving this obsession and are cheering me on. That said I have NOT been able to produce a very sour, even too sour loaf by changing the ash content. I was hoping that lowering the ash content off this last batch would result in a flavor that was different than the others, which wasn't the case. Here is the break down of Test #4.

The flour mix was a simple combination of 10% WW and 90% Harvest King (bread flour). The hydration was set at exactly 60% which didn't seem to be dry or firm once the water absorbed. I liked the feel of the hydration level with these flours. I mixed by hand and kneaded after a 15 minute rest to absorb the water. I kneaded so there was a tight gluten formed but no way near a windowpane. I then formed a ball and placed the dough in an oiled 2 litre clear dough doubler so I can keep track of fermentation progress without disturbing the container. To back up a little, I adjusted the water temperature so the mix would end at 80F and placed the fermenting dough in an 80F location above my refrigerator. It took about 14 hours to double and I noticed some larger size air pockets in the bottom third of the mass. In earlier tests I had been tipping the dough out to the work surface and shaping the dough while creating tension on the outer "cloak".

In deference to SourdoughSam's origional suggestion, I decided to try tipping the dough out on a parchment, quickly slashing (with no handling what so ever) and into the oven. It didn't spring very much and the color isn't quite the same as prior tests. The lack of shaping clearly was in evidence in the shape of the final product. The crumb wasn't sufficiently more open to justify not shaping. So in the future I will shape earlier and use standard methods for pre-shape and shaping with tension. The loaves look better and it seems more a matter of timing when you shape than anything else.

In one sense I feel like I'm back at square #1. The amount of sour flavor isn't changing much from one mix to the other even considering the ash content has been quite different. While it may be that a higher ash content will allow a higher total acid content before the dough goes to rags, I haven't been able to appreciate the difference in sour. I like the resultant flavor of the Golden Buffalo and WW flours in higher concentrations but, they are not more sour, using a standard 15 hours at 80F.

I think the next test will be with a higher hydration in an attempt to get a more open crumb, and good kneading and gluten formation toward the end of fermentation. Here are the images of the last Test #4.Eric

The results you obtained in terms of crust and crumb using the no-shaping method are nearly identical to what I was getting. You have to admit that it's not bad for a zero-effort "mix in the morning, bake when you get home from work" method. :)

Perhaps the solution to the sour is more fermentation time? The research article I referred to in the original post states that they obtained maximum flavor from their tests with a fermentation time of 20 hours at 24C using a high ash content dough. I know that sounds like a ridiculously long time to ferment, but I would say that time is the most critical factor (after all, does your starter smell more sour after 12 hours or 3 days?). You're fermenting all of your breads for the same length of time, which I would think has to play a role. Mike Avery mentioned in one of his comments above that ash content isn't everything, and that he commonly makes really sour doughs with low ash content flour.

I also note that from David's latest post (recipe for Wharf Bread) that his total fermentation time at room temperature is up to 18 hours, and if you count each of the 12 hour refrigerations as 3 hours room temperature equivalent, the total fermentation time is 24 hours!

Brian,When I try to teach myself anything new I set up a schedule that limits as many variables as possible so I can observe the impact on the product of the changes I do make.

I did notice a distinctive sour aroma after fermenting for 15 hours in all of my tests. The conclusion I have arrived at is that at 15 hours of fermenting at 80F changing the ash content of the flours didn't make a significant change in the sour flavor. So, other things must be driving the sour engine.

Looking at David's formula for Wharf Bread, the primary difference from what I have been doing is extended fermenting at variable temperatures. His results are stunning. The crumb is perfect and all that extended fermenting at cool temps is allowing the open structure. The recipe is complicated and will require a dedicated refrigerator if I want to make this on a regular basis. I don't mind that if I can get the results I'm looking for. This is the bread that drives my desire to bake.

For Eric's tests it does seem logical that if different levels of ash don't change the sour for the same fermentation time (and assuming the fermentation rate is the same), then the acid production must not be limited by the buffering capacity of the flour for that length of fermentation in his tests. What should also be true is that a longer fermentation should be possible with the higher ash flour, assuming the fermentation is going at the same rate, because of the buffering capacity of the higher ash flour. A longer fermentation with more buffering capacity should result in a higher TTA. Theoretically, that should result in a more sour flavor, if the total acid is the main determining factor of sour flavor. Lots of ifs.

Eric, one thing you might find very interesting is to test the pH of your loaves just before you bake them. You can take a small chunk of dough and set it aside when you shape, and then ferment it alongside the loaf and test the pH of the little chunk. That's what I plan to start doing at some point soon. I'm even going to try to do a bunch of tests of both the pH and the TTA, as well. I'm going to Peru on a big Inca Trail hike until 4/28, starting tomorrow, though. It'll be after that at least, before I launch off on the project TTA measuring insanity.

The thing that throws me off a little about Eric's tests, is that I would've expected those loaves to be plenty sour fermented for a mix-to-bake time of 15 hours at 80F, regardless of the ash content. So, it makes me think Eric may just have one of those starters that just doesn't produce a lot of sour flavor, all other things equal. When I do warm fermentations for that basic recipe, the bread is quite sour. I've done test loaves that seemed unpleasantly sour when fermented only a little longer than Eric fermented his, that were done in the 80s like that.

When I analyzed Dave's recipe, if the temperature is around 72F, and I guess that a few hours are spent in the 60s during the refrigeration, my models come out with lower "fermentation progress" numbers than I get for Eric's recipes. Dave's recipe analysis comes out equivalent to a few hours longer fermentation than my typical "mild higher hydration" recipes, which I would expect to result in a mild but noticeable sour flavor, much as Dave describes. So, maybe Dave and I have similar starters, and Eric may have an inherently more mild starter.

It makes sense there are going to be differences in flavor for a fermentation done at lower temperatures, even if fermented to the same final pH with the same flours as a fermentation run at 80F, like if you ferment mostly at low 70s and have a number of hours in the mid-60s during the retarding stages in Dave's recipes. It could easily be that would result in a more pleasant flavor or more complex in some way.

By the way, when I ran those fermentation comparisons that I posted in my blog and then made those stiff loaves (in the discussion with CountryBoy in the thread of that blog entry) trying to deliberately make a very sour loaf, the reason I ran them at 80-82F is just to speed up the process. It's also true that higher and lower temperatures than about 76F should favor the growth of Lactobacillus over yeast.

Mike Avery mentioned that there are well-known bakers who insist that the best sour bread is made by fermenting around 65F. So, that may be the more promising temperature range to experiment with. In my case, I just wanted to get a sense of running a longer, fuller fermentation on a stiffer, high ash loaf. At 80F, I was able to do more tests in a shorter time and was able to verify that you can increase the sour right up to unpleasantly sour following that approach for a long enough fermentation time.

I think the basic relationship between sour flavor and fermentation time at given temperature will be true at high or low temperatures. However, the quality of the sour flavor may be very different at 65F compared to 75F or 85F, even if you ferment to the same final pH and TTA. The relative concentrations of the various acids may be different, even if in total they result in about the same pH and TTA.

I don't have a way at the moment to keep the bread at a temperature in the mid-60s, and I agree with Eric that making room in the refrigerator for Dave's recipe is an issue. However, recently, while looking for a buret to use to do the titrations to determine the TTA at various stages of my fermentations, which I'm going to launch into at some point, I discovered a "refrigerating incubator" product at a lab supply house. It had a couple of cubic feet, the size of a little hotel room refrig, and could control the temperature for 4C to 50C. I'm sorely tempted to get one, so I can ferment at any temperature I want.

Just to clarify: I do the long, cold retardations in my kitchen refrigerator. I have not checked, but I assume the temperature is in the low 40's, not the 60's.

The only exceptional source of heat is the discussions with my wife about taking up so much space in our refrigerator. But these occur outside of the refrigerator itself, generally with the door closed. I don't think they have much impact on the dough.

Right, I would assume the refrigerator is around 40F. However, I was guessing that after you put it in the refrigerator, if it starts in the mid-70s, it should take a while to drop all the way down to 40F, and maybe the same on the way back up, depending on how long you leave it out to warm up and all that. Without actually measuring the temperature of the dough and loaves every couple of hours or so and knowing the exact timing, it's hard to compare the fermentation process you describe to one done at a constant 80F, but making some admittedly very rough guesses, I though it would to come out more sour than what I usually do when I make high hydration, fairly mild loaves, yet not to be anywhere near as sour as these loaves we've been playing with that ferment for 16-20 hours at temperatures around or above 80F. For me, that would be a good thing, as I find these very sour loaves to be too sour for my tastes. However, Eric seems to be getting a far less sour loaf after 15 hours at 80F than I do, for whatever reasons. It could be entirely due to our subjective assessments of sour flavor, but I'm betting that there is some other thing going on, like his starter is different or some other factor we're missing.

David-Bill,One thing that might be worth looking at is a small wine cooler. They usually hold a warmer range than a standard home refrigerator and are reasonably priced.

On my starter. Interestingly, my starter is Dr. Woods San Francisco origional that I have been feeding for over a year. It's about the same as when I first re-hydrated it. They at Sourdough International hold the position that starters are very different from various regions. I think you can make a good case either way but I haven't seen that myself. I had considered that I may be wrong that a starter is a starter is a starter and should stop being stubborn and make a new one. I have maintained several types over the years and found them all to deliver about the same flavor given a similar feeding regimen.

Yes, I guess my experience is much like yours on the whole keeping multiple different starters thing. I did play around for a while with various SI starters and they were certainly different in aroma. I mentioned to Brian, though, that I didn't feel the difference manisfested itself that much in the bread, but admittedly I've been making almost all fairly mild flavored breads for a long time, until this whole thread started up.

The truth probably lies somewhere in the middle. I still think there is a large effect on flavor from the fermentation and ash content and all that, just as discussed by Brian in the original post. However, there is not doubt different starters have an effect. I believe your starter might be somwehat different from mine, unless we perceive sour flavors very differently.

For here in NJ, where the bulk of my bread making goes on, as well as some milling and siftig and now rudimentary lab testing, I think I'm going to end up getting that refrigerating incubator at some point. It will control the temp from 4C-50C, so I can do cold as well as warm fermentations, and the size is big enough to do a couple of Kgs of flour worth of loaves and would fit a couple of 13x17 trays, also. In my parents cabin in MT, they have one of those neat little half-high wine coolers. I've hijacked it a couple of times to try some things. They are pretty neat for this application, going all the way up to 65F in the case of the one my parents have.

The Inca Trail camping trip should be fun, but as always, I'll be glad to be safe at home afterward. It should be spectacular, from everything I've heard. Good luck with the sour bread projects. I'll look forward to checking out the developments when I get back.

One thing that might be worth looking at is a small wine cooler. They usually hold a warmer range than a standard home refrigerator and are reasonably priced.

An alternative would be to look for a used freezer or refrigerator. Usually you can find 'em cheap in garage sales. shopper newspaoers or thrift stores. Also, sometimes appliance repair shops give 'em away when a client buys a new one. It's cheaper to give it away than pay a dump fee.

Then go to a home brew supply store and get an auxiliary thermostat. You can control the temperature over a wide range, within a couple of degrees, and you'll have more shelf space. Also, you can use the refrigerator to brew in... or just store beer... when you're not baking. You can also use it as a wine cooler and will have more capacity at less cost than a specialized wine cooler.

Your experiments have been very interesting, and the discussion they generated enlightening. Your goal was to arrive at a formula for really sour sourdough, like the traditional San Francisco "Wharf Bread." I gather you are still working on reaching your goal, so I thought I'd post the formula that, for me, has come closest. It makes a bread that is moderately sour but with good complexity of flavor and a dark, crunchy crust with a chewy yet tender crumb. It is not a really high hydration dough, but has nice crumb structure, I think. So, here it is:

Firm Intermediate Starter

9 oz unbleached bread flour

16 oz mature firm starter (about 65% hydration)

Small amount of water, if necessary, to bring the dough together.

Dough

All of the intermediate starter from above.

5 oz whole rye flour

22 oz unbleached bread flour

0.75 oz salt

0.25 oz (1.25 T) diastatic malt

2 cups water

Mix the intermediate starter ingredients in a bowl to incorporate all the flour. Let rest for a few minutes to allow the starter to evenly hydrate then knead for 4 minutes. Place in a clean, lightly oiled bowl and cover. Ferment 6-8 hours until the starter has nearly doubled, then refrigerate over night.

The next day, take the starter out of the refrigerator, cut into 6 pieces and let come to room temperature (about an hour). Then mix all the dough ingredients with the starter and knead to window paning. (If you use other flour combinations, you may need to add more water. The dough should be tacky but not really sticky. I knead in a KitchenAid mixer. The dough should clear the sides of the bowl but stick to the bottom.)

Place the dough in a clean, lightly oiled bowl, cover and ferment for 4 hours. It does not have to double, but, if it does, continue to ferment for the full time.

Divide the dough into 3 equal pieces and shape as desired. (I prefer boules, but batards work well too.) Place the loaves in bannetons or on semolina-dusted parchment on the back of a sheet ban. Mist the loaves with oil, place in plastic bags or cover well with plastic wrap, let proof at room temperature for 1-2 hours, then refrigerate for 8-12 hours.

Remove the loaves from the refrigerator and let warm and continue proofing to 1 1/2 times their original size. (2-4 hours).

Pre-heat oven with a baking stone and heavy pan to 475F for 45-60 minutes before baking.

Score the loaves as desired, mist them with water and transfer to the baking stone. Pour 3/4 cup hot water in the heavy pan and shut the oven door. Mist the oven wall with water 2-3 times during the first 5 minutes of baking. Then remove the heavy pan and turn the oven down to 450F.

After 15 minutes, rotate the loaves if necessary for even browning. Bake for about 30-35 minutes altogether until the loaves are nicely browned (dark, reddish-brown) and their internal temperature is at least 205F. Then, turn off the oven but leave the loaves in the oven for another 5-10 minutes.

Remove the loaves and cool on a wire rack completely before slicing.

I have made this bread with all bread flour and also substituting up to 20% of the bread flour with whole rye, whole wheat or a combination. They are all good. I have not made this particular bread with GB or first clear flour, but your experiments make me want to try that.

I have not fiddled with the hydration percent or with different kneading/folding techniques. I have introduced an autolyse a couple of times, but I don't have a firm opinion on whether it resulted in a better product or not.

If you try this formula, I would be extremely interested in how it compares to your experimental bakes.

David,Your Wharf Bread looks amazing in every respect. It looks just as I remember and the crumb is perfect. If it is nice and tangy (is that a word?) then it will be perfect. From my calculations the formula above will produce 3- 1.9 lb loaves before baking. I'm guessing maybe a little over 1.5 lb baked.

I would be interested in your thoughts on how important the starter source is as it impacts flavor. I have become convinced that it doesn't matter much as long as it is active but then I have yet to produce the perfect wharf bread.

I generally keep my "white" starter at anywhere from 65-100% hydration, depending on what I've been baking. But, I adjust the flour:water to make the intermediate starter very firm, as described. I feed my starter mostly with a high extraction flour, e.g., first clear.

I have, on occasion, used whole rye rather than bread flour for the intermediate starter and did not add more rye in the dough. This made wonderful bread. I don't have a definite opinion on whether I prefer this modification or not. This bread has been very good, regardless of how I've tweaked it, so far.

In starting out with sourdough, beginning starters tend to make very sour loaves. They also many times have longer and slower rises.

Complaints and worries about sourdough getting less sour with time (and experience).

From the biological point of view, could it be we are practicing natural selection on our starters?

The way we naturally tend to prefer a sourdough starter that raises rather quickly as opposed to developing a starter that takes longer to rise. Flavor is preferred to speed but many of us tend to loose patience with a long process.

Mini,To me it seems like Davids formula requires plenty of patience. Over all it takes about 2 days to make this bread. You are right, I prefer a one day build and bake schedule. In looking at this formula, If one were to keep a firm starter in the right quantities all aged and cool in the ready it would speed this up considerably. I think the starter would hold a few days at 40F.

I'm not sure this formula requires "patience" as much as "planning." Actually, I need to start feeding up my starter on Wednesday or Thursday. Make the intermediate starter Friday evening. Make the loaves Saturday. Bake Sunday.

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